A/Jax female mice have been immunized with chicken conalbumin or methylated human serum albumin in Freund adjuvant at three-month intervals in a two-year period of aging (to 1.0 mean life span) to examine how they develop and express tuberculin-type delayed hypersensitivities to these antigens. That experiment has been completed, and responses of this sort analyzed. The experiment yielded a large amont of unexpected but important accessory information that now is also being analyzed, for example changes with aging in qualities and quantities of 30 different mouse serum antigens as detected by crossed immunoelectrophoresis. In addition to continuing these analyses of data from the completed experiment, we shall be experimenting with the effects of food antigens on specific immunologic responses, because we have seen some evidence that these antigens can affect "age-related" changes in immunologic responses and the activities of cells like monocytes/macrophages, which in turn are pivotal for most functions of the immunologic system. To study these monocytes themselves at a source level, we have worked out methods for culturing mouse blood monocytes without feeder layers or conditioned medium supplements. We shall be characterizing these cells, comparing them in mice of different strains and ages, and observing the effects on them of feedings of selected antigens. The general decline in immunologic reactivity that we identified in our original experiment as starting at about 15 months age (about 0.6 mean life span) may be food-related or age-related. To resolve which, we are beginning an experiment comparing A/Jax and CBA mice (medium- and long-lived animals) kept under the same conditions to that age for responses to the experimental antigens conalbumin and methylated human serum albumin tested as in our original experiment with A/Jax mice.